I use Subversion command line client. But I also have Tortoise SVN installed, because some operations like log and check-in benefit from the GUI.
Tortoise SVN is a Explorer shell extension which calls a Windows executable, TortoiseProc.exe.
To use it from the command line, simply save this batch file somewhere in your path :
@echo off start "" "C:\Program Files\TortoiseSVN\bin\TortoiseProc.exe" /command:%1 /path:"%2"
Then simply call like this :
tortoise log http://src.pararlint.com/aucun/trunk
or like this
tortoise commit .
Tested on Windows with 32 and 64 bits version.